Refrigeration systems incorporating a vapor-compression cycle may be utilized to condition the environment of open or closed compartments or spaces. The vapor-compression cycle utilizes a compressor to compress a phase-changing working fluid (e.g., a refrigerant), which is then condensed, expanded and evaporated. Compressing the working fluid generates heat, which, in cooling applications, is waste heat that is discharged to ambient from the compressor and condenser. Because the waste heat is not used or recovered, the lost energy of the waste heat represents an inefficiency of most refrigeration systems.
In heating applications, such as in a heat pump system, heat stored in the compressed working fluid is extracted through the condenser to heat a space or compartment. Because efficiency of the heat pump system decreases with ambient temperature, heating may be supplemented at low ambient temperatures by a radiant electrical heat source. Radiant electrical heat sources, however, are typically inefficient and, thus, lower the overall efficiency of the heating application.
In some cooling applications, an air flow may be chilled to a very low temperature to reduce the humidity. The low temperature required to remove humidity, however, may be too low for the conditioned space or compartment within a space or compartment to be. In these cases, the dehumidified chilled air may be reheated by electric radiant heat or hot-gas bypass heat to an appropriate temperature while maintaining the low humidity level. Use of radiant electrical heat and a hot gas bypass heat to reheat over-chilled air represents inefficiencies in this type of cooling application.